Band for armatures



March 26, 1946. c. LYNN BAND FOR ARMA TURES Filed Oct. 15, 1943 INVENTOR (Zazezzc @7222. B

ATTORNEY Fi i.

Patented Mar. 26, 1946 BAND FOR ARMATURES Clarence Lynn, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 13, 1943, Serial No. 506,054

2 Claims.

My invention relates to single-layer wire bands for resisting the centrifugal force on the endturns of wound rotors of dynamo-electric machines. Since the earliest days of this art, failures of such bands have usually occurred by shearing of the solder holding the turns together, and by the end of the band pulling through the clip which holds the band. Practically no bands have failed, heretofore, by actual fracture of the banding-wire itself, until, of course, failure of the band had started by solder-failure, after which the entire band was usually destroyed.

The object of my invention is to provide a single-layer band, and a new method of applying a single-layer band, or a multiple-layer band, which overcomes this difficulty and requires suflicient force to cause the wire itself to fail before the band will fail.

In the drawing, Fig. 1 is a fragmentary longitudinal sectional view of a portion of a directcurrent dynamo-electric machine, showing a band applied on one end of the armature, and Fig. 2 is a developed view of the band, showing its manner of construction in accordance with my invention.

My invention is of general application in any place where it is necessary to secure an end of a wrapping-wire to the wire itself, without joining one end of the wire to the other end. As shown in Fig. 1, the invention is illustrated in application to the armature or rotor-member 3 of a directcurrent dynamo-electric machine which also has a. field-member or stator-member 4. The invention relates to a banding-wire 5 which is applied, in a single layer, about the periphery of the coilends or end-turns 5 of the armature-winding, to retain the winding against centrifugal force. In the particular case illustrated, the band 5 is used to hold the end turns 8 against a coil-support l, with an insulating spacer 8 inserted between the upper and lower conductors, and with an insulat ing layer 9 disposed under the band 5.

The manner of applying the band 5 is illustrated in Fig. 2. An intermediate one-hundred-eightydegree starting-loop I is first formed near one end of the wire, and the short end ll of the wire is then wrapped once around the end-turns 8 of Fig. 1, after first inserting a number of flattenedout clips l2 under the place where the finished band is to lie, the ends l3 of the clips bein fiat, as indicated by construction-lines for one of the clips l2. When the short end H has passed once around the circumference. passing downwardly from its starting-loop i 0, and coming back downwardly from the top of Fig. 2 after passing once around the circumference, completing an endturn of the banding-wire, the wire-end of this end-turn is then looped tightly in an interlocking loop through the starting-loop I0, which may conveniently be done by marking of! the point M where the interlocking loop is to be made, making a sharp bend of nearly ninety degrees at this point, leaving a straight end I5 sticking out, which is then threaded through the loop l0, pulled tight, and bent or looped back on itself, as indicated at l5, and temporarily fastened, or held, in any convenient manner (not shown).

The long end of the wire from the startingloop I0 is then wrapped tightly, in a single layer of as many turns as may be desired, around the periphery of the armature end-winding 6 (or other object is to be bound). As shown in Fig. 2, this long wire-end is shown at l 6, and is wrapped in the direction of the arrow, passing downwardly from the loop l0, and coming back downwardly from the top of Fig. 2 after passing once around the circumference, and then continuing on around and around, in a plurality of turns lying side-by-side around the circumference, until the last of this series of turns is reached, as indicated at 31. At a point preferably about displaced from the starting-loop I0, an intermediate onehundred-eighty-degree loop 38 is then formed in the wire of the turn 31, and the short, remaining wire-end 39 is wrapped around the end-turns 8 (Fig. 1) of the armature-winding, being doubled back alongside of the turn 31 and going once around, in the opposite direction as shown by the arrows on this end-turn 39, in Fig. 2. At the point 40 where this wire-end 39 comes back to the intermediate loop 38, a sharp bend of nearly ninety degrees is made, providing a straight, laterally projecting end 4 l which is threaded through said intermediate loop 38, pulled tight, and bent or doubled back against the end-turn 39, as shown at ll, so as to provide an interlocking loop or joint with the intermediate loop 38.

The starting-end I5 is then (or at any intermediate time), cut off and secured in place, and the finish-end 4| is likewise secured in place, by bending over the ends l3 of the several clips I2, so as to lie fiat against two or three turns of the band 5, as indicated at l3, and the finished band is then held together by an application of solder 42, as in the prior art.

I claim as my invention:

1. A banding-wire having a plurality of turns lying side-by-side around an object to be bound, characterized by having an end-turn, at at least one end of the banding-wire, passing around the object in the direction opposite to the next adjacent tum, said banding-wire having an intermediate loop at the place where said end-turn doubles back alongside of said next adjacent turn, the wire-end of said end-turn being threaded through said intermediate loop and doubled back against itself.

2, A banding-swirehavmg an intermediatetoneat hundred-.eighty'eflegree starting-loop therein, said". wire having a short end and a long end extending end passing once around the object to be bound,

10 from said intermediate starting-loop, said short completing an end-turn of the banding-wire, the

wire-end of the end-turn beinglooped through,

' said intermediate starting-loop, and bent back on 

